Kirchhoff, Gustav Robert cesium discovered

In 1860, Gustav Kirchhoff and Robert Bunsen discovered nonradioactive cesium in mineral water in Germany. Radioactive cesium-137, and many other radionuclides that are used in nuclear medicine, was discovered in the late 1930s by Glenn T. Seaboi and his cow orker, Margaret Melhase. 

Kirchhoff, Gustav Robert (1824-87) German physicist who, while still a student, derived the laws, now known as Kirchhoff s laws, for determining currents in electrical networks. Working in spectroscopy, he discovered the elements cesium and rubidium, and formulated Kirchhoff s laws of radiation, which stipulate that, for a given wavelength, the ratio of emission to absorption is the same for all bodies at a given temperature. 

The name comes from the Latin caesius, meaning sky blue. Cesium was discovered by Robert Wilhelm Bunsen (1811-1899) and Gustav Robert Kirchhoff (1824-1887) in 1860. They used a spectroscope on a drop of mineral water and saw previously unnoted blue lines in the spectra. Cesium is rare, but it is used in photoelectric cells and as a hydrogenation catalyst. It is also used in some atomic clocks. 

In the 1859 the chemist Robert Wilhelm Bunsen and his younger colleague, the physicist Gustav Kirchhoff, discovered a surprising phenomenon of spectroscopy. The emission and absorption spectra of an element are identical. They thus put into place an ideal tool for the discovery and identification of elements. Indeed, they themselves discovered cesium (1860) and rubidium (1861). In total, at least 20 elements were found by using spectroscopic technigues (including X-ray spectroscopy). 

The existence of these different practices was not sufficient to create a discipline or subdiscipline of physical chemistry, but it showed the way. One definition of physical chemistry is that it is the application of the techniques and theories of physics to the study of chemical reactions, and the study of the interrelations of chemical and physical properties. That would mean that Faraday was a physical chemist when engaged in electrolytic researches. Other chemists devised other essentially physical instruments and applied them to chemical subjects. Robert Bunsen (1811—99) is best known today for the gas burner that bears his name, the Bunsen burner, a standard laboratory instrument. He also devised improved electrical batteries that enabled him to isolate new metals and to add to the list of elements. Bunsen and the physicist Gustav Kirchhoff (1824—87) invented a spectroscope to examine the colors of flames (see Chapter 13). They used it in chemical analysis, to detect minute quantities of elements. With it they discovered the metal cesium by the characteristic two blue lines in its spectrum and rubidium by its two red lines. We have seen how Van t Hoff and Le Bel used optical activity, the rotation of the plane of polarized light (detected by using a polarimeter) to identify optical or stereoisomers. Clearly there was a connection between physical and chemical properties. 

Cesium was discovered in 1861 by German chemists Robert Bunsen (1811—1899) and Gustav Kirchhoff (1824—1887). They found the element using a method of analysis they had just invented spectroscopy. Spectroscopy is the process of analyzing light produced when an element is heated. The light produced is different for every element. The spectrum (plural spectra) of an element consists of a series of colored lines. 

Rubidium is a soft, silvery metal, ft is one of the most active chemical elements. Rubidium is a member of the alkali family. The alkali family consists of elements in Group 1 (lA) of the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. Other Group 1 (lA) elements include lithium, sodium, potassium, cesium, and francium. Rubidium was discovered in 1861 by German chemists Robert Bunsen (1811—1899) and Gustav Kirchhoff (1824-1887). 

Cs cesium, 55, 1860 from the Latin caesius (blue) cesium and rubidium were the first elements to be discovered—by Robert Bunsen and Gustav Kirchhoff —through their spectral lines cesium is identified by its blue lines. 

Robert Bunsen and Gustav Kirchhoff discover cesium. 

Bessemer converter for steel manufacture. German chemists Robert Bunsen and Gustav Kirchhoff discover the element cesium. Scottish physicist James Clerk Maxwell and Austrian physicist Eudwig Eduard Boltzmann independently develop statistics for analyzing the behavior of molecules in a gas. Robert Bunsen invents the magnesium light. Italian chemist Stanislao Cannizzaro convinces an international conference of chemists to use the value of atomic weights determined by Swedish chemist Jons Jakob Berzelius to standardize chemical formulas. 

EXERCISE 7.2 The element cesium was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff, who found two bright blue lines in the spectrum of a substance isolated from a mineral water. One of the spectral lines of cesium has a wavelength of 456 mn. What is its frequency ... 

Each element has its own distinctive line spectrum—a kind of atomic fingerprint. Robert Bunsen (1811-1899) and Gustav Kirchhoff (1824-1887) developed the first spectroscope and used it to identify elements. In 1860, they discovered a new element and named it cesium (Latin, caesius, sky blue) because of the distinctive blue lines in its spectrum. They discovered rubidium in 1861 in a similar way (Latin, rubidius, deepest red). Still another element characterized by its unique spectrum is helium (Greek, helios, the sun). Its spectrum was observed during the solar eclipse of 1868, but helium was not isolated on Earth for another 27 years. 

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